This invention relates to a coupler which is conveniently used when one object is to be joined detachably to another object. More particularly, this invention relates to a coupler which advantageously functions as a fastener for joining two objects of nature such that, after their mutual attachment by the fastener, they may at times be required to be separated from each other for some reason or other as in the case of the attachment of a decorative panel to the baffle plate in a speaker box, for example. Particularly in the case of a decorative panel, there is generally entailed a requirement that the panel and the plate should be joined at a plurality of points by using as many couplers besides the requirement that they should be attached to and detached from each other at will. In ensuring smooth attachment of all the couplers in position in this case, the prime requisite is that the relative position of the individual couplers should be exactly fixed and the coupler should be accurately attached at the fixed positions. Further in the case of a speaker box which gives rise to vibration in use, if the component members of the couplers themselves are not brought into fast engagement, the vibration generated in the box proper causes the loosely joined couplers to shake and adversely affect the acoustic effects the speaker box is expected to produce.
Heretofore, devices of this kind have been disclosed by Japanese Utility Model Laid-open Publication No. 99259/1976 and Japanese Utility Model Laid-open Publication No. 160742/1978, for example.
The former device has a salient feature that the range of tolerable error in the relative positions of a fitting member and a receiving member, i.e. the components of a joiner, can be broadened and the possible shaking of the joiner can be completely absorbed by a pipe-shaped resilient element disposed inside the receiving member. This device depends solely on this salient feature in fulfilling its object. Since this device necessitates provision of the resilient element besides the fitting member incorporating an engaging protuberance and the receiving member and, thus inevitably comprises three major components, it involves a problem of rendering the works of production, assemblage and fixation difficult. As such, the device has not offered satisfactory fabricability in the assembly line.
The latter device relates to a mechanism for attaching a panel to a container case, which comprises an engaging pin incorporating a swelled portion at the leading end thereof and a resilient pin-receiving member provided therein with a funnel portion incorporating at the center thereof a pin-retaining hole of a diameter smaller than the diameter of the swelled portion, with the engaging pin or the pin-receiving member being so adapted as to be attached with freedom of positional adjustment permitted by having bolts inserted with space allowance through insertion holes bored in advance in one of the fitting portions. According to this device, the space allowance provided between the insertion holes and the corresponding bolts permits desired adjustment of the relative fitting positions of the component members of the mechanism. Besides, the insertion of the engaging pin into the pin-receiving hole brings them into freely separable engagement. However, the actual positional adjustment is complicated because it necessitates the plurality of bolts to be tightened independently of one another. Once the swelled portion of the engaging pin is thrust past the pin-retaining hole, it can easily be extracted from the hole because the funnel wall converging into the pin-retaining hole is slanted opposite the direction of extraction. There is even a possibility of the swelled portion breaking the funnel portion so seriously as to render the mechanism no longer reusable.